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Sea Walls

Man-made sea walls are a familiar, and increasingly essential feature on the urbanised coast, but they come at a cost to marine creatures and intertidal habitats. Surfing scientist Ruben Meerman meets Dr Mark Browne, a scientist who has come up with a simple yet effective solution to the problem.

Duration: 3min 30sec

Broadcast:
Thu 24 Jun 2010, 12:00am

Published:
Thu 24 Jun 2010, 12:00am

Transcript

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Ruben Meerman

The picture perfect spot, but building parks and homes right on the water comes at a price, sea walls are necessary to protect our property, but spare a thought for the marine life evicted from their natural homes.

Dr Mark Browne

Places like Australia, Asia, America and Europe, more than 50 per cent of the actual shoreline's actually been replaced by these artificial sea walls.

NARRATION

Dr Mark Browne has been studying the impact of humans on marine animals and their habitats for the last 10 years.

Dr Mark Browne

Replacing natural shorelines with these artificial sea walls has huge ecological impacts. You're replacing the natural area which is about 10 to 100 metres long with a sea wall, which is basically vertical. It's very featureless, and because of its vertical surface, it actually restricts the amount of area that's available, and critical habitats such as these sort of rock pools here, which have specialist fauna in them, aren't actually present on the sea walls. Therefore there are huge impacts associated with the seawalls themselves. We're looking in these types of habitats and were finding important species of snails, anthropods, limpets.

Ruben Meerman

They're packed, there's so many little creatures here and is that a starfish?

Dr Mark Browne

It is.

Dr Mark Browne

We want to try and conserve this species and have them living on the sea walls themselves.

Ruben Meerman

These sea walls will always be here and more will be built so how can we make them more marine friendly? The answer is flower pots but not the garden variety these are built to mimic natural rock pools.

Dr Mark Browne

The aim of our project is really to add an important microhabitat that is not normally found on a sea wall, I think we can use flowerpots.

Ruben Meerman

Here they are, and what's holding them on?

Dr Mark Browne

The flower pots are held onto the wall using a galvanised metal bracket, which is then held on with four bolts

Ruben Meerman

Simple... and they're two different heights, is there a reason for that?

Dr Mark Browne

They are two different heights so that we can get organisms that normally grow on the bottom of the wall that don't normally grow on the top of the wall growing there.

Ruben Meerman

Right, so you're extending the range in a way.

Dr Mark Browne

We are, we're trying to make these walls more habitable and get more organisms on them. When the tide retreats, water's left inside the pots that then forms a rock pool, the organisms then like to live in that rock pool and therefore during the emergent time when, when the tide's out, we have a nice home for the organisms, for plants and animals to live in. In six months they actually improved the levels of biodiversity on the sea walls by up to five times.

Ruben Meerman

And what have we got in here?

Dr Mark Browne

So we've got unique species of red, green and brown algae, we've got very species of snails, limpets, anthropods, crabs and starfish. These are things that we don't normally find on sea walls but we're finding in these pots.

NARRATION

Mark's happy with the results so far and if you'd like to help out our marine neighbours take on board Mark's advice...

Dr Mark Browne

There are two approaches to improving biodiversity, one is to, when you're actually building new sea walls, to have artificial rock pools built in, but if you've got existing sea walls, we're saying to people that you are able to do something practical about biodiversity by just attaching these flowerpots onto existing walls.

Ruben Meerman

It might take a little while for these creatures to adapt to their new penthouse apartments by the sea but it's home.